Intraoperative ultrasound guided breast conserving surgery: From precise tumor excision to chest wall perforator flap partial breast reconstruction

Background Breast-conserving surgery (BCS) followed by radiotherapy is the gold-standard treatment for early breast cancer (BC). The implementation of screening programs, together with the increasing effectiveness of neoadjuvant systemic therapies, has led to a rising incidence of non-palpable BC lesions requiring reliable localization techniques. Despite being underused, IntraOperative Ultrasound-guided BCS (IOUS) stands out as the only technique providing real-time, direct visualization of both the tumor and resection margins. Furthermore, tumors traditionally considered candidates for mastectomy—such as multifocal or multicentric disease, or lesions with unfavorable anticipated resection-to-breast volume ratios (ARR)—may now be amenable to BCS owing to modern oncoplastic techniques. Among these, chest wall perforator flaps (CWPFs) for partial breast reconstruction (PBR) represent a versatile approach, enabling mastectomy avoidance in selected patients while preserving breast shape and volume without contralateral symmetrization. Methods This prospective observational cohort study compared IOUS with traditional surgery (TS, including palpation- or wire-guided surgery). Patients with ductal carcinoma in situ (DCIS), T1–2 invasive BC, or post-neoadjuvant residual lesions suitable for BCS were included. All BC lesion types were eligible and patients were stratified according to a novel lesion-type classification system. Primary objectives were to assess positive margin rates, excision volumes, and cosmetic satisfaction. In a separate cohort of patients with DCIS or stage I–III BC requiring wide glandular resections and with high ARR, IOUS combined with CWPF-based PBR was performed. Surgical, oncological, and cosmetic outcomes were prospectively evaluated to assess the feasibility of this fully IOUS-guided oncoplastic approach and its potential to reduce mastectomy rates. Results A total of 206 female patients were enrolled in the first cohort, with 103 receiving TS and 103 undergoing IOUS. IOUS resulted in significantly smaller excision volumes (p=0.024), higher tumor volume to specimen volume ratios (p=0.002), and lower involved margin and reoperation rates (p=0.002 and p=0.01, respectively). IOUS guaranteed higher patient satisfaction (p=0.001). These findings were consistent across all BC lesion types. The IOUS-guided CWPFs based PBR cohort included 73 patients. The median tumor size was 32 mm, with 43.8% of lesions being multifocal/multicentric and the median ARR being 30.2%. The median operative time was 112 min. The 30-day global complication rate was 16.4%, and no flap losses occurred. The positive margin rate was 9.6%. Both patients-reported and surgeon-assessed evaluations demonstrated excellent cosmetic outcomes. Conclusions IOUS showed clear superiority over TS in oncological, surgical, and cosmetic outcomes across all BC lesion types. The combination of IOUS and CWPFs achieved consistently favorable outcomes in challenging clinical scenarios, safely expanding the indications for BCS and reducing mastectomy rates, particularly in patients with small-to-medium breasts and unfavorable ARRs.